The cooling of integrated circuits is rapidly becoming a performance-related issue. As semiconductor processing technology progresses, for example, a larger number of transistors can fit on ever-shrinking pieces of silicon. These transistors generate heat when they operate, leading to semiconductor devices that get warmer and warmer. At some point, depending upon the materials involved, heat will degrade the performance of the circuitry on the semiconductor chip. Thermal management of the semiconductor chip includes several different approaches, ranging from simple, such as a heat sink that comes in contact with the package, to complex cooling systems with moving parts.
For example, U.S. Pat. No. 6,032,477, issued Mar. 7, 2000, and entitled xe2x80x9cMethod and Apparatus for Cooling Electrical Components,xe2x80x9d discloses a sorber and sorbent system. In this system, a sorber chamber contains a sorber fluid that is transported to and from the hot component with electrically controlled valves and removed from the surface of the component using electromagnetic energy.
In another approach, disclosed in U.S. Pat. No. 6,054,676, issued Apr. 25, 2000, and entitled xe2x80x9cMethod and Apparatus for Cooling and Integrated Circuit,xe2x80x9d the integrated circuit is inserted into a sealed, thermally insulated chamber. A cooling element inside the chamber is in contact with the integrated circuit package and is operated to cool the package, thereby cooling the integrated circuit.
A more complicated system is disclosed in U.S. Pat. No. 6,094,912, issued Aug. 1, 2000, entitled xe2x80x9cApparatus and Method for Adaptively Controlling Moving Members within a Closed Cycle Thermal Regenerative Machine.xe2x80x9d The system includes two moving parts, a motor and a power supply to operate the thermal regenerative machine to cool an integrated circuit.
An alternative approach is discussed in U.S. Pat. No. 6,250,085, issued Jun. 26, 2001, and entitled xe2x80x9cTemperature Self-Regulated Integrated Circuit and Devices.xe2x80x9d In this approach, a thermoelectric cooler that operates by running current of an opposite polarity to cool an integrated circuit is integrated into the semiconductor die on which the integrated circuit is manufactured.